1. Technical Field
The present invention relates to an optical waveguide device, and in particular, to a method for fabricating an optical waveguide device using an ultraviolet (UV) curable optical polymer to form a core with enhanced simplicity and free of contamination through back illumination of ultraviolet (UV) light.
2. Related Art
In optical communication systems, messages are transmitted by carrier waves of optical frequencies that are generated by sources such as lasers or light-emitting diodes. Optical communication systems are desirable over conventional communication systems because of a greatly increased number of communication channels and the ability to use other materials other than expensive copper cables for transmitting messages. A common device for conducting or guiding waves of optical frequencies from one point to another is an "optical waveguide." The carrier waves of optical frequencies are transmitted while at the same time confined within a particular region in the waveguide. Useful optical waveguide devices must have, for example, low optical transmission loss, low optical absorbance, facile fabrication, controllable refractive index ratios, and high heat resistance.
Contemporary optical waveguide devices and known fabrication techniques are disclosed, for example, in U.S. Pat. No. 4,609,252 for Organic Optical Waveguide Device And Method For Making issued to Wong et al., U.S. Pat. No. 4,783,136 for Optical Waveguides And Method For Making Same issued to Elman et al., U.S. Pat. No. 4,856,859 for Optical Waveguide And Method For Fabricating The Same issued to Imoto, U.S. Pat. No. 5,113,471 for Optical Waveguide Array And Method Of Manufacturing Same issued to Inaishi et al., U.S. Pat. No. 5,317,082 for Photodefinable Optical Waveguides issued to Beuhler et al., U.S. Pat. No. 5,497,445 for Polymer Core Optical Wave-Guide And Fabrication Method Thereof issued to Imoto, U.S. Pat. No. 5,541,039 for Method For Forming Optically Active Waveguides issued to McFarland et al., U.S. Pat. No. 5,598,501 for Polyimide Optical Waveguide And Method Of Manufacturing The Same issued to Marou et al., and U.S. Pat. No. 5,613,995 for Method For Making Planar Optical Waveguides issued to Bhandarkar et al. Generally, active optical waveguides have predominately been fabricated from inorganic crystalline materials. These materials in general have high dielectric constants and moderate electro-optic coefficients but require high temperature processing, and are therefore not easily fabricated and integrated with other semiconductor devices. Organic and especially polymeric organic materials are more suitable for fabrication and integration purposes because they can be processed at much lower temperatures and are amenable to solution and other chemical coating techniques. Reactive ion etching (RIE), photobleaching, or a poling induced technique is generally used to fabricate optical waveguide devices using polymeric materials. However, the substrate must be subjected to harsh conditions of lithography and liquid or reactive ion etched. These techniques, as I have observed, require additional vacuum equipments, increased fabrication time and complexity, all of which attribute to lower product yield. Moreover, contamination caused by direct contact between photomask and polymeric materials during fabrication cannot be avoided.